Cellular adhesion and migration mechanisms have been recognized as crucial elements regulating the fate and function of all leukocytes. As such, the direct visalization of cell adhesion properties and the fine structural feature that influence these properties is central to our understanding of how white blood cells Darticipate in inflammation, hemostasisT thrombosis and immunity. The Intravital Microscopy Core has been :ormulated based on a stated need of PPG investigators and is designed to draw on the considerable experience of its key personnel to provide expertise and specialized equipment in the design and execution of in vivo imaging studies on the pathophysiological role of glycosyltransferases. The Specific Aims of the Intravital Microscopy Core are as follows: 1. To execute and analyze intravital microscopy-based adhesion and migration studies in murine tissues. Currently available imaging models include: cremaster muscle; ear skin; bone marrow; liver; popliteal and inguinal lymph node; bladder; knee joint; and small intestine, including mesentery, Peyer's patches and lamina propria. 2. To provide access to and expertise and to conduct specific experiments utilizing multi-photon microscopy-based recording of intra- and extravascular blood cell adhesion, migration and cell-cell interactions in as many as six dimensions (i.e. space, time, color, fluorescence intensity). 4. To provide assistance in the planning, execution and analysis of blood cell homing in vivo employing defined models of inflammation. Services to be provided by the Imaging Core will allow participating investigators to investigate how defined glycosylation pathways influence blood cells interactions with their environment at a resolution ranging from single cells to intact animals.